Inconsistent Extrusion
Diagnose uneven extrusion that creates alternating thick and thin lines.
Inconsistent extrusion can make surfaces appear rough even when the average amount of filament is correct.
Check that the filament spool can rotate freely.
Inspect the filament path for excessive resistance.
If your printer uses a Bowden tube, make sure the filament moves smoothly through it.
Check the extruder gears for debris and make sure they are not slipping.
Partially blocked nozzles can produce changing flow rates.
Filament diameter also varies slightly between manufacturers. Very poor-quality filament may create inconsistent extrusion.
Moisture can cause bubbles and irregular flow, particularly with PETG, nylon and TPU.
Finally, consider print speed. If the hot end is close to its maximum flow rate, extrusion may become inconsistent during fast sections.
Reduce speed and compare the result.
Common causes: restricted filament path, extruder slipping, partial clog, wet filament, excessive flow demand.